The Structure of Tight Junctions in Mouse Submandibular Gland

Salivary gland cells are joined by junctional complexes consisting of a tight junction (TJ), zonula adherens and one or more desmosomes. TJs regulate paracellular permeability, maintain separate apical and basolateral membrane domains, and serve as signaling centers. We examined TJs of mouse submandibular glands (SMG) in thin sections and freeze‐fracture replicas. TJs between acinar cells and between intercalated duct cells had 2–6 parallel strands on the protoplasmic fracture face, with occasional branches, interconnections and free ends, and corresponding grooves on the extracellular face. Granular duct cell TJs had 2–30 strands, a depth of ≤0.5 μm, and occasional loops extending further basally. Where 3 or 4 cells met, the TJs extended basally ≤1 μm and consisted of 2 parallel boundary strands into which the apical strands inserted. Quantitative analyses showed significant differences in TJ complexity, measured by fractal geometry, and strand number of acinar compared to granular duct cells, and a greater number of strands in male compared to female granular ducts. Pilocarpine stimulation increased TJ strand number in female acinar cells, and increased complexity of male granular duct cell TJs. As the salivary gland water channel aquaporin 5 (AQP5) has been proposed to functionally interact with TJs to regulate salivary fluid composition, we also studied glands from AQP5 knock‐out mice. In males lacking AQP5, granular duct TJs were more complex than those of wild‐type mice, and exhibited more strands following pilocarpine stimulation. The results demonstrate specific gender, cell type and genetic differences in TJ structure and response to stimulation. Anat Rec, 2010. © 2009 Wiley‐Liss, Inc.     

Altered Serous Granules in Acinar Cells of a Human Parotid Gland

A peculiar alteration of secretory granule morphology was observed in serous cells of the parotid gland from a patient undergoing radical neck surgery for oral cancer. The granules were half filled with a dense material that in early stages of formation appeared to consist of filaments or fine tubules. Growth of these apparently rigid fibrillar structures caused the formation of long pseudopo-dia on the granule surface. Granule alterations were not due to preoperative treatment because the patient had had none. It is postulated that the granule alterations were due to a perturbation in granule composition, possibly because of a genetic mutation that led to changes in one or more of the proline-rich proteins that normally reside in parotid serous granules.     

Ciliated Cells in the Main Excretory Duct of the Submandibular Gland in Obstructive Sialadenitis: A SEM and TEM Study

The epithelium of the main excretory duct of the submandibular gland in five cases of obstructive sialadenitis was studied by TEM and SEM. In three cases we found a considerable increase in goblet and ciliated cells. As well as normal cilia, different kinds of ciliary anomalies, especially compound cilia, were noticed. Images of centriole formation and of ciliogenesis, both normal and abnormal, were also observed. Several hypotheses concerning the mode of formation of the compound cilia are discussed.     

Ultrastructural Observation of Calcification in a Pleomorphic Adenoma of the Parotid Gland

A pleomorphic adenoma was examined by electron microscopy. Calcification was found in a lumen and in epithelial cells and consisted of needle-shaped crystals that contained calcium and phosphorus and were probably apatite. Small collections of crystals in the lumen, which were often associated with membranous cellular debris, appeared to form larger calcified masses by fusion. Collections of crystals were seen in vacuoles in adluminal cells. The calcification in the lumen may have started on membranous cellular debris, and that in the adluminal cells may have arisen either by endocytosis of luminal material or by autophagocytosis. The calcification appears to relate to the old age of the tumor.     

A Role for Electron Microscopy in Salivary Gland Neoplasms

Undoubtedly, electron microscopy has a specific role to play in the diagnosis of a select group of salivary gland neoplasms. However, this tool has a current central role, along with immunohistochemical techniques, in elucidating morphogenetic processes in salivary gland tumors. New information gained from ultrastructural surveys of these tumors can be applied to improving classification and the diagnostic problems that are not infrequent for the surgical pathologist with salivary gland lesions.     

A Role for Electron Microscopy in Salivary Gland Neoplasms

Undoubtedly, electron microscopy has a specific role to play in the diagnosis of a select group of salivary gland neoplasms. However, this tool has a current central role, along with immunohistochemical techniques, in elucidating morphogenetic processes in salivary gland tumors. New information gained from ultrastructural surveys of these tumors can be applied to improving classification and the diagnostic problems that are not infrequent for the surgical pathologist with salivary gland lesions.     

Ultrastructural Morphometric Study of Follicular Center Lymphocytes: II. Analyses of Cleaved-Cell Populations Do Not Support the Lukes-Collins' Concept

Ultrastructural morphometric analysis was carried out on six cases of lymph node biopsies with reactive hyperplasia to establish the frequency and depth of invaginations in nuclear profiles situated in the mantle zones and follicular centers. The frequency distribution of the depth of invaginations was similar in nuclear profiles whether in the small lymphocytes of mantle zones or the small, partially transformed (centrocytes) and fully transformed (centroblasts) lymphocytes of follicular centers. Invaginated and cleaved lymphocytes were not confined to the partially transformed (centrocytic) lymphocytes of follicular centers, and nuclear profiles with invaginations bore no resemblance to those depicted in the Lukes-Collins model. A considerable proportion of mantle zone lymphocyte nuclear profiles had invaginations (ranging from 7.5% to 53.6%) and there was no difference between the frequency of deep indentations or clefts in mantle zone lymphocytes (8.1 ± 5.4%) and the small unstimulated (9.3 ± 5.3%) and partially transformed (8.4 ± 1.4%) lymphocytes in follicular centers. Computer modeling of stylized nuclei with conical indentations indicated that all lymphocytic nuclei likely have multiple invaginations or groove-like creases.     

Ultrastructural Morphometric Study of Follicular Center Lymphocytes: I. Nuclear Characteristics and the Lukes-Collins' Concept

A combined ultrastructural and morpnometric image analysis study was carried out on the nuclear profiles of follicular center and mantle zone lymphocytes of six cases of reactive hyperplasia in human lymph node biopsies. For accuracy of morphological observations and sampling at low magnifications, sections were mounted on formvar-covered slot grids. Measurements of nuclear profile features of small (untransformed) lymphocytes in mantle zones served as the standard for a supposed unimodal population in each case. Analysis of nuclear profile area values indicated that during lymphocyte transformation in follicular centers nuclei had a gradual and progressive increase in size and that the sampled nuclear profiles in both the mantle zone and follicular center were unimodal. Lymphocyte nuclear shape (contour index) was a more complex, and likely biologically independent, feature than nuclear area in both the mantle zone and follicular center. Nuclear profile contour indexes of mantle zone lymphocytes were more irregular than suspected and in some cases had mean values greater than those of follicular center lymphocytes. Furthermore, the frequency distribution of nuclear contour index was not normally distributed in either the follicular center or mantle zone due to the presence of a small proportion of highly irregularly shaped nuclear profiles in both sites. The results indicated that some premises of existing concepts of follicular center cells and the process of lymphocyte transformation in follicular centers were incorrect and should not be directly extrapolated to the nuclear profile characteristics in non-Hodgkin's lymphoma.     

Ultrastructural and Immunohistochemical Study of Salivary Duct Carcinoma of the Parotid Gland

A case of salivary duct carcinoma of the parotid gland found in an 81-year-old man was studied by light microscopy, immunohistochemistry, and electron microscopy. Histologically, the tumor was composed of elongated cords of cells and ductal structure with desmoplastic stromal reaction. Tumor cell nests sometimes showed central comedonecrosis. Immuno-histochemically, the tumor cells were positive for cytokeratin and epithelial membrane antigen, and they were negative for S-100 protein and muscle-specific actin. Electromicroscopi-cally, two cell types were identified. The first cell type showed electron-lucent cytoplasm with scant organelles. The second type cell contained numerous mitochondria. Neither acinar nor myoepithelial cell differentiation was observed. These findings suggest that salivary duct carcinoma originates from the interlobular or excretory ducts.     

Diabetic Status Influences the Storage of Melatonin in Human Salivary Glands

Recently we reported on the detailed localization of melatonin (and its receptors) in human salivary glands, revealing that serous cells are able to store and secrete melatonin into saliva. Since we found that type 2 diabetic patients display reduced melatonin content in saliva, our next step was to examine the presence of melatonin in salivary glands removed from type 2 diabetic subjects. The resulting data were compared with those previously obtained by identical procedures in non‐diabetics, to establish if the diabetic status may affect melatonin distribution. Bioptic samples of diabetic parotid and submandibular glands were fixed, dehydrated, embedded in Epon Resin and processed to demonstrate melatonin reactivity by the immunogold staining method. The labeling density (expressed as the number of gold particles per μm²/granule) and the percentage of melatonin‐positive granules were assessed in diabetic samples. These values were compared with those in non‐diabetic samples and differences were evaluated. In parotid and submandibular diabetic glands the reactivity for melatonin was specifically associated with secretory granules and small vesicles in serous cells. Melatonin reactivity was higher in parotid than in submandibular glands. Our data were in line with those obtained in our previous study on non‐diabetic glands. Diabetic salivary glands showed a higher labeling density and a lower number of melatonin‐positive granules compared to non‐diabetic glands. Taken together, these data might explain the decreased salivary melatonin content and the associated oral problems observed in diabetics. Anat Rec, 301:711–716, 2018. © 2017 Wiley Periodicals, Inc.     

成人下颌下腺微血管构筑

目的　了解成人下颌下腺微血管的构筑特点及分布规律,为下颌下腺减量移植提供解剖学依据。 方法　对摘除的正常下颌下腺进行墨汁、福尔马林灌注固定并切片,光镜下观察腺体的血管构筑的形态特点 和分布规律。结果　成人下颌下腺小叶内的纹管及腺泡周围血管网的血供主要来源于微前动脉,腺泡周围血 管网部分接受纹管周围血管网的供血,两个血管网有各自的静脉回流。在小叶内存在动—动,静—动,静—静 吻合;在小叶间导管存在动—动,静—静吻合。结论　下颌下腺的血管构筑特点为下颌下腺减量移植提供解 剖学依据,下颌下腺减量移植是可行的。     

Development and Prevention of Morphologic and Ultrastructural Changes in Uremia-induced Hyperplastic Parathyroid Gland

The detailed ultrastructural changes of uremia-induced hyperplastic parathyroid gland and the effects of current medical treatments for secondary hyperparathyroidism were investigated. Marked enlargement of parathyroid cell with accumulation of mitochondria and lipids and a significant increase in the thickness of the pericapillary area with increased fibrosis and appearance of fibroblast like cells were noted in the hyperplastic gland caused by uremia and phosphate retention. These ultrastructural changes and biochemical findings indicating hyperparathyroidism were significantly suppressed by all of the treatment using phosphate restriction, calcitriol, and cinacalcet. The characteristic ultrastructural changes, including the morphologic evidence of nodule formation, were indicated.     

Vascularity in Nontumorous Human Pituitaries and Incidental Microadenomas: A Morphometric Study

The aim of the present study was to determine the microvascular angioarchitecture in the lateral and central portions of the anterior lobe as well as of the posterior lobe. The possible association between vascularity and age, sex, and pregnancy was also examined. In addition the vascular density of incidental microadenomas was investigated and compared to that of nontumorous gland. Blood vessels of 120 nontumorous pituitaries and 11 incidental microadenomas obtained at autopsy were examined by immunohistochemistry using the endothelial marker CD 34. Microvascular density (MVD) and microvessel surface density (MSD) were determined by morphometry using an automatic computer image analysis system. MVD and MSD were higher in the anterior than in the posterior lobe. Age, gender, or pregnancy did not affect the angioarchitecture of these sites. No statistical differences in MVD and MSD were observed between central and lateral areas of the anterior lobe, although MVD appeared to be lower in the lateral zones. A marked difference was noted in the vascularity of microadenomas compared to nontumorus tissue; both MVD and MSD were significantly lower in adenomatous tissue. Our studies suggest that the capillary network of the anterior and posterior lobes differ. They also indicate that the microvascular architecture is not significantly affected by age, gender, or pregnancy. Lack of significant angiogenesis in pituitary microadenomas may underlie the low growth rate and infrequency of metastasis of pituitary adenomas.     

Signet Ring Cell Carcinoma of the Stomach: A Morphometric, Ultrastructural, and DNA Cytometric Study

The present study was undertaken to determine whether or not signet ring cell (diffuse, isolated cell) gastric carcinomas display a specific profile at the ultrastructural, morphometric, and DNA cytometric levels. Thirty-two cases of gastric carcinoma and 8 cases of peptic ulcer (control group) were studied with electron microscopy, morphometry, flow cytometry, and image cytometry. Despite the ultrastructural cellular heterogeneity of signet ring cell carcinomas, the neoplastic cells display fairly constant morphometric features: The cellular and nuclear volumes are significantly smaller than those of the other types of gastric carcinomas and closely resemble those of normal foveolar cells. The relatively small size of signet ring cell carcinoma nuclei fits with the high percentage of the cases of this type of gastric carcinoma that are either diploid or nearly diploid. There is a relationship between the infiltrative pattern of growth of gastric carcinoma (regardless of histologic subtype and ultrastructural cell differentiation) and the small size of neoplastic cells and their nuclei.     

Motor and Secretory Effects of Nerves on the Parotid Gland of the Rat

The influence of parasympathetic and sympathetic nerves on the parotid gland of the rat was investigated. It was found that both divisions of the autonomic nerves evoke secretion and probably also motor effects in this gland. Secretion elicited on sympathetic stimulation was mediated both via α- and β-adrenoceptors, while motor effects were mediated via α-adrenoceptors. On stimulation of the autonomic nerves a lower duct pressure was reached in the parotid than in the submaxillary gland, and on sympathetic nerve stimulation the flow of saliva always started later from the parotid than from the submaxillary gland. These findings are discussed in the view of the different arrangement of the myoepithelial cells in the 2 glands.     

High-Resolution Ultrastructural Study of the Rat Glomerular Basement Membrane in Long-Term Experimental Diabetes

The ultrastructure of the glomerular basement membrane of the long-term diabetic and age-matched control rats was studied with the application of advanced high-resolution microscopy. By using the freeze substitution method for the preparation of the renal tissue, it was possible to observe that the glomerular basement membrane in control and diabetic animals is composed of only a single lamina densa without the presence of a lamina lucida interna or externa. High-resolution electron microscopy of the diabetic glomerular basement membrane showed significant alterations in its morphology and ultrastructure. First, the basement membrane in diabetic condition appeared to be split into two halves, endothelial and epithelial. In the epithelial half of the membrane, the network of distinct strands referred to as cords, which were clearly present in the glomerular basement membrane of age-matched control animals, became less distinct and showed a diffused appearance being evenly replaced by thin filaments. The openings of the network were filled with a granular material. In the endothelial half of the membrane, on the other hand, the cord network was variably lost in diabetic condition and, within the resulting vacant spaces, bundles of fibrils 12 nm in width, identified as basotubules, were deposited. Immunolabeling for type IV collagen was found to be enriched in the endothelial half of the basement membrane being associated with the bundles of basotubules. The ultrastructural changes reported by high-resolution microscopy could be related to the molecular alterations of the basement membrane components and to the loss in permselectivity occurring during diabetes.     

成人下颌下腺微血管分布和测量

目的探讨成人下颌下腺微血管构筑特点,为临床下颌下腺游离移植提供形态学资料。方法应用显微解剖学方法观察测量成人下颌下腺微血管构筑和分布特点。结果成人下颌下腺深浅两部位的血管密度不同,深部腺体的血管密度高于浅部腺体的血管密度。腺内血管密度排列依次为深前区、深后区、浅前区及浅后区。结论提示下颌下腺减量游离移植时,深前区、深后区为易成活的优质供腺部位。     

Subpopulations of Human Lung Alveolar Macrophages: Ultrastructural Features

Lung alveolar macrophages (LAM), obtained by bronchoalveolar lavage of healthy donors, were separated into four subfractions on discontinuous gradients of Percoll and subjected to light micro-scopic, transmission (TEM) and scanning electron microscopic (SEM) studies. Alveolar macrophage morphometric analysis was performed on cytocen-trifuged preparations. TEM of subpopulations revealed considerable morphologic heterogeneity. By SEM, cells of the most dense (D) subtraction were small, round, and, typically, the surface was highly ruffled with small membrane pseudopods. Cells of the least dense subtraction (A) showed a low degree of membrane folding or filopodia and were often totally disorganized.

In smokers, macrophages of fraction A had a greater area and perimeter compared with non-smokers, whereas the inverse relationship was observed for C and D cells. Also, the number of electron-dense inclusions and the level of acid phosphatase were higher in smokers than in non-smokers. Coupled with functional heterogeneity the morphologic differences described in this paper suggest that density-separated subpopulations of LAM may represent different stages of differentiation or maturation.